Huge Swing

July 24, 2020


Inspired by the Colin Furze 360-swing video, I wanted to try out building a large swing set. I haven't really done any large projects like this before, but I figured I would test out my civil engineering abilities with this structure. Particularly, I wanted to test out the possibility of building this scale swing set by using supporting cables, so that there will be significantly less steel than the Furze design, and significantly less material cost. Of course the swing would have to really make a statement, so the main columns are designed to be 20 ft tall, with the swing section being solid as well and thus capable of going up to 40 ft at peak extension.


In theory, all that is needed for the swing set is two supporting columns, and four anchor points to which cables would run from the top of the columns (two from each) to stabilize them against lateral forces of the swing motion. The bottom of the columns would only need to be kept stable laterally and there would not be a moment load on the columns so there is no requirement for excavation. To improve safety, as I would rely on these cables to keep me from crashing into the ground, I added 6 more cables, for a total of 10 ground anchors and cables, 5 on the top of each column. In addition, I initially thought of using steel for the columns as that was in the Furze design, but on considering material costs and necessary load handling, I concluded that 4x4 wood beams would hold the load, be much cheaper, and be much easier to machine. Thus the swing set consists of large wood columns and steel wire rope supports attached to ground anchors. The use of the ground anchors greatly expands the base area of the structure and its stability, while keeping material consumption to a minimum. Additionally, of the remaining metal components, I modified the design whenever possible to use simple angle sections which are drilled and assembled by hand, removing any need for milling or turning. This was necessary both to simplify my workload and because the covid shutdowns meant all machine shops were closed or inaccessible. The following was the bill of materials:


The current and future economic climate means I won't be owning land any time soon and probably not ever. This places significant limitations on my ability to assemble big projects like this. For this project, I rented a cabin with adjacent cleared land, for 5 days. Thus I had to assemble, test, and tear down the swing within these 5 days. The failure of this project was due to this very compressed time frame and the inability to continue working over a longer term. I did assemble the swing and all the parts worked correctly. However by the time the assembly was complete, it was time to do the teardown, and thus I never got the opportunity to erect the structure and test it out. It was a frustrating loss compounding to this frustrating year. Photos of the assembly are provided below.

In the absence of a lathe, I had to come up with a more creative solution to decrease the diameter of the steel rod. I put together a jig with roller bearings and used an angle grinder, to create a sort of centerless grinding arrangement. It worked decently well, through the surface finish was rough.

4 inch angle sections assembled to connect to wire ropes.

12 inch angle sections assembled to connect to bearings.

All the materials loaded into a car.

The main wood columns once assembled, and the ground foundation using leveled concrete blocks.

The rigid swing section with supporting cross-beams and a wooden handle.


I was unable to test whether the wood structure supported by ground anchors would hold up to the expected swing loads, which was very unfortunate as that was the goal of this project. Still based on what it looked like from the ground, I believe the structure would have worked. Nonetheless I was able to draw a few conclusions from this experience: